Septic tank



-May 4 1926. 1,582,915

E. W. FARLEY SEPTIC TANK Filed May 1, 1923 nwwi'mmnn'u '1 I lilil mentoz fit tox n e1;

Paten'ted May 4, 1926.

UNITED STATES ERNST W. IABLEY, F RICHMOND,

SEPTIC TANK.

' Application filed May 1,

The object of my invention is toprovide a septic tank which shall be non-porous; which shall be inexpensive to build, and

adapted to shipment to considerable distances; and which shall also oifer the greatest resistance. to the corrosive action of the sewage and other wastes which it is purposed to treat in it. i

In the past septic tanks have been constructed of several kinds of material; such as brick, ,wood, concrete, iron, steel, etc.

Brickwork wasfound to be too permeable;

wood rapidly deteriorated.- Steel and iron plate were then tried. These materials made tight, inexpensive, and easily transported tank's; but their life was comparatively short when subjected to the corrosive action of the acid and alkaline compounds to be found in sewage, and to the bacterial reactions taking place during the putrefying of the solids. To overcome the objections to the short life of such tanks, concrete, molded in place, was then largely used; and is used to this day, and for the same reason. Large septic tanks built up of concrete are much 55 more costly than steel tanks of like capacity; the material for their construction must be shipped to the site, and they must be built in place; it is very difiicult to stop leaks, which frequently exist around the,

epipe connections, inlets and outlets; the body of the tanks is permeable; voids in the walls are common; and the tanks are not portable. At the same time such concrete tanks, when ,well built, have been preferred to the steel tank for the reason noted. One of the functions of a septic tank is to provide a chamber or chambers in series in which the bacterial reactions may take place. Manifestly, if the wall or walls of the chamber or chamhers is destro ed by corrosion, or even badly perforated, tie function of the tank is also destroyed, and a menace is created.

I have discovered that'the rapid corrod-'- 1928. Serial No. 635,354.

ing of the steel of the tank may be practically checked by alloying with the steel a small percentage of copper; approximately one quarter of one percent. V g The form of septic tank I have reference to is shown in the accompanying drawin in which 1 is the bod of the tank; 2 is t e 5 cover; 3 is the inlet or thesewage; 4 is a bafile to prevent the agitation of the surface of the sewage in'themain chamber 5 by the inflowing sewage; 6' is a baflle attached to the dividing plate 7 andover the orifice 8;

' 9 is a closed. battle and outletchamber covering the outlet 10, andin the top of which. is the vacuum breaking valve 11'. The lighter solids collect on the surface of the hquid in the main chamber 5, where their c-ondition is changed by bacterial action; the said action continuing as the liquid passes through the chambers to the outlet 10, through which it may be discharged to irrigation beds or to other means for purification and for fertilization of the soil. "1 In a tank of ordinary steel the surface is protected to some extent by the ap lication of a coating of some material suc as as-' "phaltum; but once this coating is broken, so

the rusting process begins, and .the progress of the corrosion under the rust coat is rapid. A tank made of copper-steel may also be coated with paint, asphaltum or like material, if desired; but it'has been found that where the surface of the copper-steel is exposed there forms a thin rust coat, and that this rust coat of the copper-steel itself forms F such an efficient protective coating that the further corrosion of the metal is practically 00 stopped. 7 1

Though the most efiicient results have been obtained by alloying one quarter of one percent of copper with the steel, yet good results have been obtained with somewhat smaller and also somewhat larger percentages of copper. In ordinary steel the corrosion rate appears to be progressive, while with the copper-steel the rate of resistance to corrosion 1s progressive. -In tests made .to compare the corrosion 0f-,the' ordinary steels with a copper-bearing steel it was found that the ordinary steel was practically destroyed in six months, while t e coppersteel, though subjected to the same test con- 1 jditions, was in practically as good condition limit myself to the articular design of sep-' in the sixth month as the ordinary was atthe end of the first month; and it was also noted, by comparing the loss in metal from month to month, that the corrosion of: the copper-steel was then practically arrested; The use of, copper-stee in the manufacture of my septic tanks permits me to use a design which has great advantages in the proper treatment of the sewage; but which design would not be as durable as would be a simpler one were I limited tothe use of ordinary steels. At the same time, I do not tic tank illustrate and described herein,

since it-is obvious that this design maybe modified without departing from the spirit .of my mventi'on- In my copending application Ser. No. 578,106, filed July 28; 1922, I claim structural details of septic tanks.

1. A septic tank formed of an alloy consisting of copper and steel.

' 2. A septic tank formed of an alloy consisting of steel and approximately one'quar- 8'6 ter. of one per cenf of copper.

In testimony whereof I have hereunto aifixed my sighature.

ERNST W. FABLEY. 

